Network Topologies

Network Topologies

A network can be configured or arranged in different ways. The physical layout or arrangement of connected devices in a network is called topology. It is the shape of a network . Different network topologies are as follows:

• Bus Topology

Bus topology is the simplest type of network.It supports a small number of computers. In bus topology, all computers or network nodes are connected to a common communication medium.This medium is often a central wire known as bus. The terminators are used at the end of a bus to absorb signals.A collision can occur in bus topology if two computers transmit data at same time .Bus topology is mostly used in peer-to- peer networks.

• Working of Bus Network 

The sending computer sends the data and destination address through the bus. The data and address move from one computer to the other in the network. Each computer checks the address. If it matches with the address of a computer, the computer keeps the data.Otherwise the data moves to the next computer.
Advantages 

1. It is simple and easy to use.
2. It requires small length of  cable to connect computers. 
3. It is less expensive.
4. It is easy to extend a bus . It allows more computers to join network. 
5. If one node fails, it does not affect the rest of the network.

 Disadvantages 

1. It is difficult to troubleshoot . 
2. It only supports small number of computers.
3. The network speed slows down as the number of computers increases.

 Star Topology

All computers in star topology are connected with central device called hub, star topology is mostly used in client- server networks. 

Working of Star Network

The sending computer sends the data to hub.The hub sends data to the receiving computer. Each computer in star network communicates with a central hub.

Advantages

1. It is easy to maintain and modify network.
2. Adding or  removing computers can be done without disturbing the network.
3.  Finding faults becomes very simple.
4. Single computer failure does not bring down the  whole network.
5. It is more flexible than other topologies.
   

Disadvantages:

1. It central hub fails, the entire network breaks down
2. It requires a large length of cable to connect computers.
3. It is more expensive.

Rind Topology

In ring topology, each computer is connected to the next computer with the last one connected to the first. Thus a ring of computers is formed.

Working of Ring Network

Every computer is connected to next computer in a ring . Each computer  receives message from the previous computer and transmits it to the next computer. The message flows in one direction. The message is passed around the ring until it reaches the correct destination computer.

Advantages

1. It is less expensive than star topology.
2. Every computer has equal access to the network.

Disadvantages

1. Failure of one computer in the ring can affect the whole network. 
2. It is difficult to troubleshoot.
3. Adding or removing computers affect the whole network.